Re: Video of Seichiro Endo Shihan
When I was at Honbu for four and a half years starting about ten years ago, I attended every Endo Shihan class I could and was fortunate to take ukemi from him a number of times. His main teaching seemed to be that once one learned the basic techniques, one should play with them, "research" as he called it. Unlike many of the other shihan, he did not overtly teach certain ways to take ukemi, but it became clear that he wanted uke and nage to really respond to what the other was doing, not just follow the "kata." There was a period where at the end of each class, he would come over and throw me for about five minutes. I always attempted to keep in constant motion, looking for openings. I would vary the speed and type of attack and Sensei easily moved with whatever I did.
I don't know Endo Shihan's feelings about demonstrations. My impression has been that the various Shihan either are not too fond of them but feel that they have to do them or else they view it as a chance to show (off?) what they can do. My guess is that Endo Shihan is in the first group, but I really don't know.
There was an interesting article in his dojo's newsletter written by a student of his who is a professor in a German university about six years ago that dealt with Szcepan's criticisms. The writer compared the usual style of aikido practice, what she called "aikido in collusion" with Endo Shihan's style, which she called "aikido in co-evolution."
In Collusion, both tori and uke move according to what is in their heads, ignoring what is physically happening at that moment. They are colluding in acting out a representation of a martial encounter, but the result is that they become stiff, they start the "kata" from a far too great distance, and any deviation is responded to by fear and anger (really the same thing.)
In Endo Shihan's co-evolution aikido, uke and tori start much closer to each other and all conditions are variable. Movement, attacks and even the tori/uke roles can change at any moment. As Jaime wrote above, the result is that both people become "heavier" what the writer describes as "gluey and permeable simultaneously. Atemi is extensively employed but in Endo Shihan's case is very light or at lease guaged on uke's ability to take a hit. (Unlike for ex. Yasuno Shihan who WILL hit you.)
Szcepan's criticisms are interesting for me as I feel that a number of the Shihan whom he admires are in the "collusion" category. As an example, their waza always look the same no matter the size or temperment of the attacker. Also many Shihan's uke will stop in the middle of an attack even if they are in a dangerous position, and wait for the teacher to "do" the technique. I have a video of one of these Shihan in which he loses connection with his uke, who stands up. The Shihan gives him a "look" (the look my mother often gave me when I messed up) and the uke put himself back into a precarious position so the Shihan could finish the technique!
Just one guy's opinion, but Endo Shihan is the best Aikido practitioner I have ever felt or seen. There are some interesting articles on his Saku Dojo's website. I highly recommend them.